Fix RideEditor crash on last delete

If you delete the last ride and scroll down in the ride editor
GC will crash. This patch ensures the model is invalidated when
a ride is deleted.

src/RideFileTableModel.cpp

@@ -57,6 +57,9 @@ RideFileTableModel::deleted()
 {
     // we don't need to disconnect since they're free'd up by QT
     ride = NULL;
+    beginResetModel();
+    endResetModel();
+    dataChanged(createIndex(0,0), createIndex(90,999999));
 }
 
 void